1. Field of the Invention
The invention relates to helicopter anti-torque control utilizing engine exhaust in a unique manner. The helicopter configuration is a single rotor configuration.
2. Prior Art
Typically, in a single rotor helicopter, anti-torque and directional control is achieved by a tail rotor, with the magnitude of the torque produced being controlled by tail rotor collective control.
A number of designs have been suggested according to which the tail rotor is replaced by air jets located in the tail boom of the helicopter. In some of these designs, engine exhaust is used as a working medium directed out of the jets.
One such design is disclosed in U.S. Pat. No. 2,486,272, which uses engine exhaust gases to supply the intake of an air compressor which in turn provides compressed gas for both propulsion and anti-torque control.
Another design disclosed in U.S. Pat. No. 2,518,697 uses exhaust gas mixed with engine cooling air. Other designs are disclosed in U.S. Pat. Nos. 3,015,460 and 3,957,226.
Using exhaust gas for anti-torque control, while perhaps convenient, carries with it the inherent problem of IR (INFRA RED) detection, i.e., the air jet output carries the same IR signature as that of the exhaust gas. In a combat situation, this condition is clearly unacceptable.
It would, therefore, be desirable to have an anti-torque control which utilizes engine exhaust but which also substantially reduces, IR levels.